Glaucoma e inquinamento

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Secondo alcuni ricercatori della Harvard Medical School di Boston, l’inquinamento atmosferico da particolato può aumentare il rischio di sviluppare glaucoma, specialmente quando esiste una vulnerabilità genetica. Gli studiosi hanno analizzato 419 anziani residenti nella zona di Boston che partecipavano dagli anni Sessanta a un più ampio studio sull’invecchiamento condotto dallo U.S. Department of Veterans Affairs. I partecipanti sono stati sottoposti a esami clinici ogni 3-5 anni, tra cui la misurazione della pressione intraoculare. Successivamente, i ricercatori hanno esaminato i risultati dell’inquinamento confrontandoli con quelli della pressione oculare di ciascun partecipante, tenendo conto di una serie di altri fattori legati alla salute e allo stile di vita, come il fumo, presenza di cardiopatie, ipertensione e diabete.

In generale, lo studio non ha registrato associazioni tra l’inquinamento e la pressione oculare. Tuttavia, quando ha considerato solo gli uomini che presentavano determinate caratteristiche genetiche che li rendevano più vulnerabili allo stress ossidativo, ha scoperto un legame significativo tra livelli più elevati di inquinamento e un leggero incremento nella pressione oculare: “Di frequente, quando pensiamo al glaucoma pensiamo a fattori di rischio come età e predisposizione genetica e non consideriamo l’ambiente”, dichiara il dott. Jamaji Nwanaji-Enwerem, autore principale dello studio condotto sugli effetti delle minuscole particelle di particolato di diametro inferiore a 2,5 micron. L’articolo è stato pubblicato sulla rivista scientifica JAMA Ophthalmology online 2018; di seguito ne riportiamo l’abstract.

JAMA Ophthalmol. 2018 Nov 8. doi: 10.1001/jamaophthalmol.2018.5313. [Epub ahead of print]

Association of Long-term Ambient Black Carbon Exposure and Oxidative Stress Allelic Variants With Intraocular Pressure in Older Men

Nwanaji-Enwerem JC, Wang W, Nwanaji-Enwerem O, Vokonas P, Baccarelli A, Weisskopf M, Herndon LW, Wiggs JL, Park SK, Schwartz J.

IMPORTANCE
Elevated intraocular pressure is a major risk factor for glaucoma, a leading cause of irreversible blindness worldwide. Environmental air pollution has been suggested as a potential contributor to elevated intraocular pressure; however, no studies have demonstrated such an association to date.

OBJECTIVE
To investigate the association of long-term ambient black carbon exposure with intraocular pressure in community-dwelling older adults.

DESIGN, SETTING, AND PARTICIPANTS
This population-based analysis, conducted from October 18, 2017, through March 22, 2018, used data from the all-male, New England-based Normative Aging Study of the US Department of Veterans Affairs. The analysis included 419 older men with a total of 911 follow-up study visits between January 1, 2000, and December 30, 2011. Intraocular pressure was measured by Goldmann applanation tonometry during the study visits. Validated spatiotemporal models were used to generate 1-year black carbon exposure levels at the addresses of the participants.

MAIN OUTCOMES AND MEASURES
An independently developed genetic score approach was used to calculate allelic risk scores for 3 pathways associated with black carbon toxicity: endothelial function, oxidative stress, and metal processing. The associations among black carbon exposure, allelic risk scores, and intraocular pressure were explored using linear mixed-effects models.

RESULTS
All 419 participants were men with a mean (SD) age of 75.3 (6.9) years. The mean (SD) 1-year black carbon exposure was 0.51 (0.18) µg/m3, and the mean (SD) intraocular pressure for the left eye was 14.1 (2.8) mm Hg and for the right eye was 14.1 (3.0) mm Hg. Of the 911 visits, 520 (57.1%) had a high endothelial function allelic risk score, 644 (70.7%) had a high metal-processing allelic risk score, and 623 (68.4%) had a high oxidative stress allelic risk score. In fully adjusted linear mixed-effects models, the association of black carbon with intraocular pressure was greater in individuals with a high oxidative stress allelic score (ß=0.36; 95% CI, 0.003-0.73) compared with individuals with a low score (ß=-0.35; 95% CI, -0.86 to 0.15).

CONCLUSIONS AND RELEVANCE
Ambient black carbon exposure may be a risk factor for increased intraocular pressure in individuals susceptible to other biological oxidative stressors. If additional studies confirm these results, monitoring ambient black carbon exposure and physiological oxidative stress may prevent the development and progression of intraocular pressure-related disease.